"M" Class Destroyer (1914)

A total of 103 destroyers of the "M" Class were completed, 13 in the 1913-1914 programme and 90 further ships as part of the successive orders of the War Emergency Programme.

They were essentially improved "L" class destroyers with 6 knots more speed, but there was a mix of Admiralty design vessels (79) and a diverse set of builder's specials (22 ships).

The War Emergency Programme ships are often called the Repeat "M" Class, but the distinction between them and the original 13 vessels is largely fiduciary and less important than the design differences attributable to specials and Admiralty design as well as the manic diversity the Royal Navy's ships exhibited even when it intended a uniform class. For this convoluted reason, "Repeat 'M' Class" will be used in a passing manner here, and all 103 ships generally called "M" class destroyers.

Overview of 103 vessels
Citations for this data available on individual ship pages
Name	Builder	Laid Down	Launched	Completed	Fate
Matchless	Swan Hunter		5 Oct, 1914		Oct, 1921
Murray	Palmer		6 Aug, 1914		May, 1921
Myngs	Palmer		24 Sep, 1914		May, 1921
Milne	John Brown		5 Oct, 1914		Sep, 1921
Moorsom	John Brown		20 Dec, 1914		Nov, 1921
Morris	John Brown		19 Nov, 1914
Mons	John Brown		1 May, 1915
Marne	John Brown		29 May, 1915
Mystic	Denny		26 Jun, 1915
Maenad	Denny		10 Aug, 1915
Manners	Fairfield		15 Jun, 1915
Mandate	Fairfield		27 Apr, 1915
Magic	J. S. White		10 Sep, 1915
Moresby	J. S. White		20 Nov, 1915
Marmion	Swan Hunter		28 May, 1915		Collision 21 Oct, 1917
Martial	Swan Hunter		1 Jul, 1915
Mary Rose	Swan Hunter		8 Oct, 1915		Sunk 17 Oct, 1917
Menace	Swan Hunter		9 Nov, 1915
Mameluke	John Brown		14 Aug, 1915
Marvel	Denny		7 Oct, 1915
Mischief	Fairfield		12 Oct, 1915
Mindful	Fairfield		24 Aug, 1915
Nonsuch	Palmer		8 Dec, 1915
Negro	Palmer		8 Mar, 1916		Collision 21 Dec, 1916
Nessus	Swan Hunter		24 Aug, 1915		Collision 8 Sep, 1918
Noble	A. Stephen		25 Nov, 1915
Nizam	A. Stephen		6 Apr, 1916
Nomad	A. Stephen		7 Feb, 1916		Sunk 31 May, 1916
Nonpareil	A. Stephen		16 May, 1916
Norman	Palmer		20 Mar, 1916
Northesk	Palmer		5 Jul, 1916
North Star	Palmer		9 Nov, 1916
Nugent	Palmer		23 Jan, 1917
Obedient	Scott		6 Nov, 1915
Obdurate	Scott		21 Jan, 1916
Onslaught	Fairfield		4 Dec, 1915
Onslow	Fairfield		15 Feb, 1916
Opal	Doxford		11 Sep, 1915
Ophelia	Doxford		13 Oct, 1915
Opportune	Doxford		20 Nov, 1915
Oracle	Doxford		23 Dec, 1915
Orestes	Doxford		21 Mar, 1916
Orford	Doxford		19 Apr, 1916
Orpheus	Doxford		17 Jun, 1916
Octavia	Doxford		21 Jun, 1916
Ossory	John Brown		9 Oct, 1915
Nestor	Swan Hunter		9 Oct, 1915		Sunk 31 May, 1916
Napier	John Brown		27 Nov, 1915
Template:UK-Narbrough	John Brown		2 Mar, 1916		Wrecked 12 Jan, 1918
Narwhal	Denny		30 Dec, 1915		Collision 1919
Nicator	Denny		3 Feb, 1916
Norseman	Doxford		15 Aug, 1916
Oberon	Doxford		29 Sep, 1916
Observer	Fairfield		1 May, 1916
Offa	Fairfield		7 Jun, 1916
Orcadia	Fairfield		26 Jul, 1916
Oriana	Fairfield		23 Sep, 1916
Oriole	Palmer		31 Jul, 1916
Osiris	Palmer		28 Sep, 1916
Paladin	Scott		27 Mar, 1916
Parthian	Scott		3 Jul, 1916
Partridge	Swan Hunter		4 Mar, 1916
Pasley	Swan Hunter		15 Apr, 1916
Plucky	Scott		21 Apr, 1916
Portia	Scott		10 Aug, 1916
Pheasant	Fairfield		23 Oct, 1916		Mined 1 Mar, 1917
Phoebe	Fairfield		20 Nov, 1916
Pigeon	Hawthorn Leslie		3 Mar, 1916
Plover	Hawthorn Leslie		3 Mar, 1916
Penn	John Brown		8 Apr, 1916
Peregrine	John Brown		29 May, 1916
Pelican	Beardmore		18 Mar, 1916
Pellew	Beardmore		8 May, 1916
Petard	Denny		24 Mar, 1916
Peyton	Denny		2 May, 1916
Prince	A. Stephen		26 Jul, 1916
Pylades	A. Stephen		28 Sep, 1916
Medina	J. S. White		8 Mar, 1916
Medway	J. S. White		19 Apr, 1916
Mastiff	Thornycroft		5 Sep, 1914
Meteor	Thornycroft		24 Jul, 1914
Michael	Thornycroft		19 May, 1915
Milbrook	Thornycroft		12 Jul, 1915
Minion	Thornycroft		11 Sep, 1915
Munster	Thornycroft		24 Nov, 1915
Nepean	Thornycroft		22 Jan, 1916
Nereus	Thornycroft		24 Feb, 1916
Patrician	Thornycroft		5 Jun, 1916
Patriot	Thornycroft		20 Apr, 1916
Rapid	Thornycroft		15 Jul, 1916
Ready	Thornycroft		26 Aug, 1916
Miranda	Yarrow		27 May, 1914	Aug, 1914
Minos	Yarrow		6 Aug, 1914
Manly	Yarrow		12 Oct, 1914
Moon	Yarrow		23 Apr, 1915
Morning Star	Yarrow		26 Jun, 1915
Mounsey	Yarrow		11 Sep, 1915
Musketeer	Yarrow		12 Nov, 1915
Nerissa	Yarrow		9 Feb, 1916
Relentless	Yarrow		15 Apr, 1916
Rival	Yarrow		14 Jun, 1916
Mansfield	Hawthorn Leslie		3 Dec, 1914
Mentor	Hawthorn Leslie		21 Aug, 1914

Machinery

Generators

In 1916, it was stated that "new destroyers" have two 26.25 kw dynamos arranged in parallel. It is possible that this applied to some or all of this class.

Performance

Admiralty M

The ships' capacity for 285 tons of fuel, delivered the following endurance.

Knots	Tons / hour	Endurance (hours)	radius (nm)
14	2.0	135	1,890
16	2.5	108	1,728
18	3.2	84	1,512
20	4.0	67	1,340
22	5.0	54	1,1188
24	6.2	43	1,032
26	8.2	33	858
28	10.8	25	700
30	12.5	21	630

Yarrow M

The ships' capacity for 255 tons of fuel, delivered the following endurance.

Knots	Tons / hour	Endurance (hours)	radius (nm)
14	1.8	133	1,862
16	2.2	109	1,744
18	2.8	85	1,530
20	3.4	70	1,400
22	4.5	53	1,166
24	5.5	43	1,032
26	7.0	34	884
28	8.5	28	784
30	10.5	22	660

Thornycroft M

The ships' capacity for 275 tons of fuel, delivered the following endurance.

Knots	Tons / hour	Endurance (hours)	radius (nm)
14	1.6	162	2,268
16	2.0	130	2,080
18	2.4	108	1,944
20	3.2	81	1,620
22	4.2	62	1,364
24	5.6	46	1,104
26	7.0	37	962
28	9.0	29	812
30	11.5	22	660

Armament

4-in Guns

Their three 4-in Q.F. Mark IV guns on P IX mountings on the centre line were just as in the preceding "L" class destroyers and the final seven of the Acasta class. There were 120 rounds per gun: 36 common, 84 lyddite, an an additional 19 practice rounds.

The mounting could elevate 20 degrees and depress 10 degrees, but its sight could only elevate 15 degrees and the range dial was actually only graduated to 12.5 degrees (7,900 yards). "This was soon remedied by the supply of additional sight strips graduated to the extreme range of 10,200 yards."

These gear-worked sights had gearing constants of 26.66 and range dials for 2200 fps, and 1-in aiming rifle. MV could be corrected by a cam pointer allowing for a decrease to 2000 fps.

Unlike some P IX sights, these were not F.T.P. sights.

The midship gun was supplied with ammunition from the forward stores.

The deflection gearing constant was 52.6 with 1 knot equal to 3.18 arc minutes, corresponding to 2200 fps at 2000 yards. Drift was corrected by inclining the sight about pivot pins 2 degrees.

The layer's telescope sight line was 12.5 inches above the bore, and 21.45 inches left. The trainer's telescope sight line was 12.5 inches above and 17.4 inches right. Open sights were 13.3 inches above the bore and 24.35 inches left for layer and 20.3 inches right for trainer.

The sight had a temperature correcting scale plate and a "C" corrector.

The layer had an open sight. The trainer's sight could be used as a free sight with a counterweight.

During the war, some of the ships were required to land their aft gun to accommodate depth charges.

Other Guns

They may have carried one (later two) 1-pdr H.A. guns (later 2-pdr) as well as 4 mines on the upper deck. The first six ships were to complete with H.A. pompoms, and the others to receive theirs as they became available.

By 1920, some or all had one 2-pdr pompom for air defence.

Torpedoes

As in the preceding class, they had two twin 21-in tubes on the centre line enjoying 50 degree arcs centered on the beam.

Other Weapons

Depth charges were added to most destroyers, necessitating that some land their aft gun to accommodate the outfit.

Fire Control

Range and Order Instruments

By the end of 1915, at least, these ships had or were to be provided a range and order data system similar recent Barr and Stroud patterns.

The scheme placed the combined transmitter on the forebridge, and a combined receiver near the sightsetter position of each gun. Ranges from 0 to 9900 yards in increments of 100 yards, and orders were "Independent", "Control" and "Fire" with illuminated indicators and a red indicator on the receivers to signal loss of power from the battery pack located below decks.

Alterations

By November 1918, Prince and Meteor were fitted to carry 38 mines. The torpedo tubes and guns removed when the mines were shipped could be placed back aboard with enough notice.

See Also

• Medea Class Destroyer (1914)
• Wikipedia

Bibliography

• Gray, Randal (editor) (1985). Conway's All the World's Fighting Ships 1906–1921. London: Conway Maritime Press. (on Amazon.com and Amazon.co.uk).
• Admiralty, Technical History Section (1920). The Technical History and Index: Alteration in Armaments of H.M. Ships during the War. Vol. 4, Part 34. C.B. 1515 (34) now O.U. 6171/20. At The National Archives, Kew, United Kingdom.
• March, Edgar J. (1966). British Destroyers: A History of Development, 1892-1953. London: Seeley Service & Co. Limited. (on Bookfinder.com).